A modern battery-powered electronic device can monitor the charge level of one or more batteries in the electronic device. Typically, when the battery level falls below a predetermined threshold value of remaining charge, then the electronic device notifies the user with a message such as “battery low” or other visual and/or audible indicator of the remaining charge level.
Often, a “battery low” indication that is based on a fixed threshold of charge remaining is not received in time for the user to take a corrective action. For example, if a user typically charges her smart phone at night, but forgets to do so on one occasion, receiving a “battery low” indication just before leaving for work the next day does not leave the user time to charge her phone before work.